Original Entry by Xu Zhang
What is a nanopore?
A nanopore is a small hole in an electrically insulating membrane, that can be used as a single-molecule detector. It may be considered a Coulter counter for much smaller particles. It can be a biological protein channel in a high electrical resistance lipid bilayer or a pore in a solid-state membrane.
The detection principle is based on monitoring the ionic current of an electrolyte solution passing through the nanopore as a voltage is applied across the membrane. When the nanopore is of molecular dimensions, passage of molecules (e.g., DNA) cause interruptions of the "open" current level, leading to a "translocation event" signal.
Solid-state nanopores are generally made in silicon compound membranes, one of the most common being silicon nitride. Solid-state nanopores can be manufactured with several techniques including ion-beam sculpting and electron beams.
Nanopores are making contributions to the understanding of polymer biophysics, as well as to single-molecule analysis of DNA-protein interactions.